WHITES are now in the minority in nearly one in 10 US counties because of immigration and a higher birth rate among blacks and Hispanics.

And the increased diversity is straining race relations and sparking a backlash against immigrants in many communities with complaints that many refuse to embrace the local culture.

"There's some culture shock," said Mark Mather of the Population Reference Bureau, a Washington-based research agency. "But I think there is a momentum building, and it is going to continue."

As of 2006, non-Hispanic whites made up less than half the population in 303 of the nation's 3141 counties, according to latest census bureau figures. Non-Hispanic whites were a minority in 262 counties in 2000, up from 183 in 1990 ...

Many of the US's biggest counties have long had large minority populations. But that diversity is now spreading to the suburbs and beyond, causing resentment in some areas.

Many Latinos say they see it in the debate over illegal immigration.

In northern Virginia, Teresita Jacinto said she feels less welcome today than when she first arrived 30 years ago, when she was one of few Hispanics in the area.

"Not only are we feeling less welcome, we are feeling threatened," said Ms Jacinto, a teacher in Woodbridge, Virginia.

Woodbridge is part of Prince William County, which recently passed a resolution seeking to deny public services to illegal immigrants.

Similar measures have been approved or considered in dozens of communities across the US. In all, state MPs have introduced more than 1400 measures related to immigration this year, the National Conference of State Legislatures says.

Supporters say local laws are necessary because Congress has failed to crack down on the estimated 12 million illegal immigrants in the US. But many Hispanics legally in the US say they feel targeted, too ...

Nationally, the number of minorities topped 100 million for the first time in 2006 — about a third of the population. By 2050, minorities will account for half of US residents, according to bureau projections ...